## 问题：如何将负数转换为正数？

How can I convert a negative number to positive in Python? (And keep a positive one.)

## 回答 0

``````>>> n = -42
>>> -n       # if you know n is negative
42
>>> abs(n)   # for any n
42
``````

``````>>> n = -42
>>> -n       # if you know n is negative
42
>>> abs(n)   # for any n
42
``````

Don’t forget to check the docs.

## 回答 1

``````>>> -10 * -1
10
>>> 10 * -1
-10
``````

simply multiplying by -1 works in both ways …

``````>>> -10 * -1
10
>>> 10 * -1
-10
``````

## 回答 2

``````>>> abs(-1)
1
>>> abs(1)
1
``````

If “keep a positive one” means you want a positive number to stay positive, but also convert a negative number to positive, use `abs()`:

``````>>> abs(-1)
1
>>> abs(1)
1
``````

## 回答 3

``positivenum = abs(negativenum)``

The inbuilt function abs() would do the trick.

``````positivenum = abs(negativenum)
``````

## 回答 4

``````In [6]: x = -2
In [7]: x
Out[7]: -2

In [8]: abs(x)
Out[8]: 2
``````

``````In [6]: x = -2
In [7]: x
Out[7]: -2

In [8]: abs(x)
Out[8]: 2
``````

Actually `abs` will return the `absolute value` of any number. Absolute value is always a non-negative number.

## 回答 5

``````import numpy as np
np.abs(-1.23)
>> 1.23
``````

If you are working with numpy you can use

``````import numpy as np
np.abs(-1.23)
>> 1.23
``````

It will provide absolute values.